Conventionally, an analysis method using a geometric-optical model is widely known as a method for analyzing the propagation characteristics of radio wave (for example, see Non-Patent Document 1).
FIG. 1 shows a method for obtaining a radio wave propagation path by a conventional ray trace method.
As shown in FIG. 1, the conventional ray trace method includes three steps. The first step determines an image point T′ of a transmission point T with respect to a wall surface 1 and then determines an image point T″ of the image point T′ with respect to a wall surface 2.
In the second step, T″ and a reception point R are connected to each other with a straight light, and a point where the straight line and the wall surface 2 intersect to each other is obtained. The intersection point thus obtained is a reflection point X2 on the wall surface 2.
In the third step, the reflection point X2 on the wall surface 2 and T′ are connected to each other with a straight line to obtain a reflection point X1 on the wall surface 1.
In this case, the propagation distance takes the same value as a length of the straight line connecting T″ and the reception point R to each other. The electric field intensity at the reception point R can be obtained using the propagation distance.
FIG. 2 shows a conventional method for obtaining the propagation paths of a transmitted wave and a reflected wave (for example, see Non-Patent Document 2).
Further, Patent Document 1 discloses a method for estimating propagation characteristics for a case in which a transmission direction is other than a rectilinear direction, and a reflection direction is other than a specular reflection direction.